The present invention relates generally to electromagnetic transducers and, more particularly, to an electromagnetic transducer for applying an oscillatory force to a load.
A great variety of electromagnetic transducers are known in the art. Two general categories are moving coil designs and so-called moving iron designs. These latter designs are sometimes referred to as variable reluctance devices. In general, the variable reluctance designs are capable of producing high forces in a compact volume and at a higher efficiency than moving coil designs. Such transducers, however, have not typically been useful when high linearity is desired since the basic relationship between the excitation current and the resulting force is in accordance with a square law and is thus non-linear.
Among the several objects of the present invention may be noted the provision of a magnetic attraction or variable reluctance transducer which is essentially linear in response; the provision of such a transducer which exhibits high efficiency; the provision of such a transducer which can generate high forces in a compact volume; the provision of such a transducer which is highly efficient and which is operable over a relatively wide frequency range; the provision of such a transducer which is highly reliable and which is of relatively simple and inexpensive construction. Other objects and features will be in part apparent and in part pointed out hereinafter.